Electrical terminal blocks and mounting rails



A. R. NORDEN 3,259,876

ELECTRICAL TERMINAL BLOCKS AND MOUNTING RAILS July 5, 1966 Filed Sept.11, 1963 FIG. 3 H KY W @/Z M Uh LIE! my f6 F/QZ r1 v @imi' L I v FIG. 4

INVENTOR.

United States Patent 3,259,876 ELECTRICAL TERMINAL BLOCKS AND MOUNTINGRAILS Alexander R. Norden, 350 Central Park W., New York 25, N.Y. FiledSept. 11, 1963, Ser. No. 308,126 8 Claims. '(Cl. 339198) The presentinvention relates :to electrical terminal blocks and to mounting meansfor such terminal 'blocks.

Electrical terminal blocks are widely used in such apparatus as motorcontrol centers, elevators and similar wired apparatus, for providingterminal connections. A given piece of apparatus usually involves alarge number of circuits requiring external connection. An individualterminal block for each circuit makes connection to a wire in theapparatus, and the terminal block provides a terminal for connecting thewire of the apparatus to an external wire. Various pieces of circuitapparatus require various numbers of terminal blocks, and these may beof various current-carrying capacities. In meeting this situation, ithas become common to assemble a number of terminal blocks for providingthe necessary number of terminals of the necessary ratings. All theterminal blocks are of a certain modular size or multiple thereof, andthe requisite complement of terminal blocks are mounted in a row,side-by-side.

An object of the present invention resides in the provision of a novelform of securing means for modular terminal blocks that is readilyadapted to accommodate various numbers of terminal blocks. A morespecific object of the invention resides in the provision of a novelmounting rail that can easily be cut down from a standard length thatcan hold a maximum number of terminal blocks to a shorter length toreceive some smaller number of modular terminal blocks. Mounting railsfor terminal blocks pursuant to the present invention can be made quitestrong in relation to the service requirements, and yet portions ofstandard, long mounting rails are easily removed to provide the desiredlength corresponding to the number of terminal blocks to be mounted. Inthis way, long connector-mounting rails can be stocked and can readilybe adapted to receive shorter rows of terminal blocks.

As will be seen, the connectors that are described in detail below havedepending portions that are gripped Ibetween confronting Walls of aresilient metal channel that forms a mounting rail. Each terminal blockmay have metal parts of different sizes corresponding to thecurrentcarrying capacity of that terminal block. The metal parts in anygiven terminal block may provide terminals for one, two or threeseparate circuits. Where more than three circuits are to beaccommodated, and where large values of current limit a terminal blockto two or one circuit, a row of terminal blocks is assembled. Theindividual terminal blocks are of a given modular size, measured alongthe mounting rail.

Another feature of the invention resides in the provision of cooperatingformations on the terminal blocks and the mounting rail that initiallyfacilitate mounting of the terminal blocks at regular modular positionsalong the rail, and which thereafter retain each mounted terminal blockin position. A further object of the invention resides in the novel formof the mounting rail for facilitating the mounting of any individualterminal block on the rail and for accommodating its removal from therail 'as may be required from time to itme, without disturbing companionterminal blocks already mounted and without unduly weakening themounting rail.

The nature of the invention and the foregoing objects and features, aswell as further features of novelty and other objects, will be readilyappreciated from the fol- 3,259,876 Patented July 5, 1966 lowingdetailed description of a preferred embodiment of the invention and of amodified mounting rail, shown in the accompanying drawings.

In the drawings:

FIGURE 1 is an enlarged lateral view of a portion of a typical mountingrail, embodying features of the present invention;

FIGURE 2 is a plan view of the mounting rail in FIG. 1;

FIG. 3 is an end view of the rail of FIG. 1, shown partly in section atthe vertical plane 3-3 of FIG. 1;

FIGURE 4 is an enlarged end view, partly in section, of the mountingrail in FIGS. 13, with a typical terminal block mounted thereon,illustrating further features of the invention;

FIGURE 5 is an enlarged lateral view of a portion of a mounting rail asin FIGS. 1-3, with a terminal block mounted thereon, shown partly insection as viewed from the section line 5-5 in FIG. 4;

FIGURE 6 is a diagrammatic illustration of a mounting rail and a singleterminal block mounted thereon, illustrating the strain involved inremoving a terminal block from a mounting rail; and

FIGURE 7 is a fragmentary plan view resembling FIG. 2 of a modifiedmounting rail, embodying features of this invention.

Referring now to the embodiment in FIGURES 1-6 inclusive, mounting rail10 is formed of a channel of relatively thin resilient sheet steel,whose vertical side walls have edge portions 12 that are turned in at amoderate angle. A row of notches 14 is formed in each of the in-turnededge portions 12 at regular modular positions along the mounting rail,and at each of these positions there is a generally oval hole 20 in thebottom of the channel. Openings 16 in the side walls are formed midwaybetween each edge slot 14 and the next one along the side wall, theseopenings being closed at the top by bridging portion 18 so as to formwindows. These windows 16 and bridging portions 18 occur in directlyopposite pairs in the side walls of the channel.

As seen in FIGURES 4 and 5, terminal blocks 22 motmted on rail 10 areprovided with depending portions 24 whose outer surfaces initiallydiverge upwardly and provide wedge surfaces 24a that are used during themounting of the terminal block on a mounting rail. Nibs 26 project fromthe lower wedge surfaces 24a (FIGURE 4) midway along the terminal block22 as viewed in FIGURE 5. The terminal block illustrated in FIGURE 5 isof a single modular size, it being understood that terminal blocks ofmultiples of this modular size (measured along the rail) may also bemounted on rail 10. Depending portions 24 of terminal block 22 haveupwardly converging surfaces 24b above surfaces 24a so that dependingportions 24 are of reduced cross-section, as shown in FIGURE 4, andprovide recesses that receive in-turned edge portions 12 of the mountingrail 10. The recesses in terminal block 22 which are thus provided forreceiving edge portions 12 are interrupted by integral ribs or webs 28that are aligned with nibs 26. Terminal block 22 also has a pair of legs29 that are of the right length to abut a surface to which rail 10 issecured w hen edge portions 12 grip surfaces 24b.

The illustrated terminal block contains metal parts for two separatecircuits. Each circuit terminal block includes a conductor 32 in theform of a metal strip, and a pair of wire clamps 30 at the ends,respectively, of conductor 32. The internal details of the terminalblock here involved do not form any part of the present invention, andare more fully disclosed and claimed in my copending application, SerialNo. 271,160, filed April 8, 1963.

The use of the terminal block and mounting rail de- 'ice scribed abovemay now be explained. A mounting rail is selected that is at least aslong as is required for receiving the necessary complement of terminalblocks 22. Rail "10 is initially much longer than required in mostapplications. The excess length of rail may easily be removed. Thebridging portion 18 in each in-turned edge 12 of the confronting sidewalls of the mounting rail are cut, conveniently by means of diagonalcutting pliers. The mounting rail is then bent, in the direction tospread the cut edges of the bridging portions 18. It may be necessary tobend the rail back and forth, but it quickly breaks across the bottom ofa channel. Because the mounting rail is of resilient sheet metal,usually thingage spring steel, it tends to fracture when bent sharplyand breaks quickly when subjected to back-and-forth bending. The brokenedge of the bottom of the channel tends to curve downward, so that anysharpness resulting from the break is directed toward the ultimatesupport to Which the rail is secured and there is no hazard from suchbroken edge.

The shortened rail thus provided is next mounted on a supportingsurface, usually by a screw at each end of the mounting rail received inholes 20. Where a long mounting rail is involved, one or more additionalmounting screws may be used at points distributed along the length ofthe rail. Next, the desired complement of terminal blocks 22 having beenselected, an individual terminal block 22 is mounted by disposingdepending portions 24 between the in-turned edges 12 of the rail. Theterminal block may be moved along these edges and the proper location ofthe terminal block is quickly reached when the nibs 26 at the oppositesides of portions 24 find corresponding notches '14 in edge portions 12of the mounting rail. Thereupon, the terminal block is forced down,portions 24 being driven slightly toward each other and the Walls of thechannel being spread somewhat apart, the deflection of the dependingportions 24 and of the channel side walls depending on their relativestillness. Where the connector body is of tough insulating material suchas nylon, both the terminal block and the mounting rail yield during theforcible movement of the terminal block into its mounted position. Whenthe terminal block has been driven all the way down, edge portions 12 ofthe mounting rail grip inward sloping surfaces 24b of the dependingportions 24, thus retaining terminal block 22 in its mounted position.Ribs 28 are received in notches 14, FIG. 5. By virtue of thisconstruction, a terminal block 22 that has beenmounted cannot shift outof its mounted position, lengthwise along rail 10. As thus located, eachterminal block 22 is in a position that does not interfere with themounting of like modular terminal blocks in the adjoining modular spacesof the mounting rail, identified by windows 16, and no end-stops areneeded to prevent the end terminal blocks of a row from slipping oif theends of the rail.

Bridge portions 18 provide great strength of the mounting rail, forresisting the stress that is imposedon the mounting rail when anindividual terminal block 22 is to be removed. This operation isdiagrammatically il lustrated in FIGURE 6, wherein mounting rail 10 isshown secured to a supporting surface 34 by fastening means at points A,A. When a terminal block 22 is being pulled away from the mounting rail,the stress impoesd on rail 10 tends to cause the rail to arch upward, inthe manner shown (greatly exaggerated) inFIGURE 6. Bridging portions 18provide great strength in resisting such imposed stress. When a directlyopposite pair of such bridging portions 18 are cut, it becomesrelatively easy to break the channel for providing short lengths ofmounting rail, as described above. Only one terminal block 22 isillustrated in FIGURE 6, but it will be appreciated that the illustratedterminal block 22 represents only one terminal block of a large numberof such terminal blocks mounted Slde-'by-Sld6 along rail 10.

It will be appreciated that many modifications may be made in thedetails of the terminal block and mounting rail described above, whileretaining the novel features thereof. A distinctive modification of themountingrail 10 is illustrated in FIGURE 7, having special merit. Rail10 is in all respects the same as rail 10 described above,

except that only one window 16' is provided at any one transverse plane,such window being bridged by an edge portion 18; Opposite each window 16is a notch or slot 116 that extends all the way from the bottom of thechannel to the edge, thus omitting a bridging portion 18'. It has beenfound that one bridging portion 17' at each transverse cross-section ofthe rail provides a great deal of strength that resists a stress such asis represented in FIGURE'6. However, by virtue of the slots 116 thatrecur at regular modular intervals along one of the side walls ofchannel 10', the intervening side wall portion 36 -is separated from thenext adjoining portions 36 of that side wall, and is thus more resilientthan in the embodiment of FIGURES l-6. This facilitates mounting andremoval of an individual terminal block 22. Moreover,

because only portion 36 deflects in the mounting or the 1. Incombination, a mounting channel for modular electrical terminal blocks,and a side-by-side series of modular electrical terminal blocks thereon,each said electrical terminal block including depending portions whichhave lateral upwardly diverging surfaces and upwardly convergingsurfaces above and adjoining said upwardly diverging surfaces, saidmounting channel having upwardly extending side walls that confront saidupwardly diverging surfaces and inwardly extending edge portions on saidside walls in tight gripping engagement with said upwardly convergingsurfaces, said side walls having transversely aligned windows formedtherein at regularly spaced intervals marking the molul'ar spaces alongthe mounting channel corresponding to said modular terminal blocks, saidwindows of at least one side wall being closed by bridging integralside-wall edge portions, said in-turned edges having notches formedtherein at modular intervals along the channel between said windowopenings, said upwardly diverging surfaces having locating nibsextending therefrom in vertical alignment with said notches andeach saidterminal block having integral portions extending into said notches forarresting said terminal block in position against movement lengthwise ofthe mounting channel.

2. In combination, a mounting channel for modular electrical terminalblocks, and a side-by-side series of modular electrical terminal blocksthereon, each said electrical terminal block including dependingportions which have lateral upwardly diverging surfaces and upwardlyconverging surfaces above and adjoining said upwardly divergingsurfaces, said mounting channel having up- Wardly extending side wallsthat confront said upwardly diverging surfaces and inwardly extendingedge portions on said side-walls in tight gripping engagement with saidi upwardly converging surfaces, said side walls having transverselyaligned pairs of windows formed therein at regularly spaced intervalsmarking the modular spaces along the mounting channel corresponding tosaid modular terminal blocks, at least one window of each pair beingclosed by bridging integral side-wall edge portions,

said in-turned edges having notches formed therein at modular intervalsalong the channel between said windows, said upwardly diverging surfaceshaving locating nibs extending therefrom in vertical alignment with saidnotches.

3. In combination, a mounting channel for modular electrical terminalblocks, and a side-by-side series of modular electrical terminal blocksthereon, each said electrical terminal block including dependingportions which have lateral upwardly diverging surfaces and upwardlyconverging surfaces above and adjoining said upwardly divergingsurfaces, said mounting channel having upwardly extending side wallsthat confront said upwardly diverging surfaces and inwardly extendingedge portions on said side walls in tight gripping engagement with saidupwardly converging surfaces, said side walls having transverselyaligned pairs of windows formed therein at regularly spaced intervalsmarking the modular spaces along the mounting channel corresponding tosaid modular terminal blocks, at least one window of each pair beingclosed by bridging integral side-wall edge portions, said in-turnededges having notches formed therein at modular intervals along thechannel between said windows, and each said terminal block havingintegral portions extending into said notches for arresting saidconnector in position against movement lengthwise of the mountingchannel.

4. In combination, a mounting channel for modular electrical terminalblocks, and a side-by-side series of modular electrical terminal blocksthereon, each said electrical terminal block including dependingportions which have lateral upwardly diverging surfaces and upwardlyconverging surfaces above and adjoining said upwardly divergingsurfaces, said mounting channel having upwardly extending side wallsthat confront said upwardly diverging surfaces and inwardly extendingedge portions on said side walls in tight gripping engagement with saidupwardly converging surfaces, said in-turned edges having notches formedtherein at modular intervals along the channel, said upwardly divergingsurfaces having cating nibs extending therefrom in vertical ailgnmentwith said notches and each said terminal block having integral portionsextending into said notches for arresting said terminal block inposition against movement lengthwise of the mounting channel.

5. In combination, a mounting channel for modular electrical terminalblocks and a side-by-side series of modular electrical terminal blocksthereon, said channel having an elongated bottom portion and elongatedside walls extending upward from said bottom portion, said side wallshaving formed therein a series of openings formed therein at modularintervals along the channel and extending to the bottom of the channel,said openings being arranged in pairs transverse to the channel and atleast one opening of each pair having the top thereof closed by anintegral bridging portion of the side wall, said side walls and saidterminal blocks having interengaging formations for retaining theterminal blocks on the channel against removal therefrom and againstdisplacement along the channel out of the modular positions defined bysaid pairs of openings.

6. A mounting rail for retaining a series of modular terminal blocks,including an elongated metal channel having a bottom portion and sidewalls extending upward therefrom, said side walls having formed thereina series of openings spaced apart at modular intervals along thechannel, said openings in the side walls being aligned in pairstransverse to the channel and said openings extending down to the bottomportion of the channel, at least one of said openings of each alignedpair having the top thereof closed by an integral bridging portion ofthe corresponding side wall, and said side walls having formationsbetween said openings for interengagement with corresponding formationsof terminal blocks.

7. A mounting rail in accordance with claim 6, wherein said retainingformations include top marginal laterally projecting portions extendingfrom said side walls.

8. A mounting rail for retaining a series of modular terminal blocks,including an elongated resilient metal channel having a bottom portionand confronting side walls extending upward therefrom, the uppermostedge portions of the side walls being turned in at an angle toconstitute terminal-block retaining elements, said side walls havingformed therein a series of openings spaced apart at modular intervalsalong the channel, said openings in the confronting side walls beingaligned in pairs transverse of the channel and at least one of saidopenings of each aligned pair being closed by an integral bridgingportion of the side wall along the uppermost edge portion thereof, oneopening of each pair extending the full height of the side wall in whichit is formed, thereby to divide the side wall into longitudinal portionsseparated from each other in successive modular spaces along the railfor independent lateral deflection during insertion and removal ofterminal blocks at the respective modular spaces.

References Cited by the Examiner UNITED STATES PATENTS 2,709,211 5/1955Glynn 339-147 X 2,885,652 5/1959 Rowe 339198 2,905,923 9/ 1959 Hammerly339198 2,943,294 6/1960 Norden 339--l98 X FOREIGN PATENTS 1,087,849 9/1954 France. 1,206,354 8/1959 France.

PATRICK A. CLIFFORD, Primary Examiner.

ALFRED S. TRASK, Examiner.

5. IN COMBINATION, A MOUNTING CHANNEL FOR MODULAR ELECTRICAL TERMINALBLOCKS AND A SIDE-BY-SIDE SERIES OF MODULAR ELECTRICAL TERMINAL BLOCKSTHEREON, SAID CHANNEL HAVING AN ELONGATED BOTTOM PORTION AND ELONGATEDSIDE WALLS EXTENDING UPWARD FROM SAID BOTTOM PORTION, SAID SIDE WALLSHAVING FORMED THEREIN A SERIES OF OPENINGS FORMED THEREIN AT MODULARINTERVALS ALONG THE CHANNEL AND EXTENDING TO THE BOTTOM OF THE CHANNEL,SAID OPENINGS BEING ARRANGED IN PAIRS TRANSVERSE TO THE CHANNEL AND ATLEAST ONE OPENING OF EACH PAIR HAVING THE TOP THEREOF CLOSED BY ANINTEGRAL BRIDGING PORTION OF THE SIDE WALL, SAID SIDE WALLS AND SAIDTERMINAL BLOCKS HAVING INTERENGAGING FORMATIONS FOR RETAINING THETERMINAL BLOCKS ON THE CHANNEL AGAINST REMOVAL THEREFROM AND AGAINSTDISPLACEMENT ALONG THE CHANNEL OUT OF THE MODULAR POSITIONS DEFINED BYSAID PAIRS OF OPENINGS.